This invention relates to "space frames", used as self-supporting roofs or ceiling systems in buildings, where an unobstructed span is desired in both length and width. A space frame includes upper and/or lower panels interconnected by struts. The substantially plane panels or "skins" are loaded in compression or tension, depending upon the three-dimensional truss loading pattern of a particular system.
This disclosure is concerned primarily with the production of such a system from plywood panels, which typically are supplied in rectangular sheets of limited width and length. One task faced by any designer of a plywood structure is that of utilizing the limited dimensions of available plywood in the production of spans that are a multiple of such limits. While plywood can be produced at the mill in extended length sheets by use of scarf joints and other end-to-end bonding techniques, these methods require expensive presses and forming machinery. They are only of limited value where increased dimension is necessary in both length and width of a sheet. Such methods normally cannot be carried out at a building site, and the ultimate sheet size that can be produced at a mill is limited by size limitations during shipment from the mill to a building site.
Space frames in general have been previously utilized to span a building area. Many of these have used self-supporting skeletal frames covered by a non-structural skin of lightweight metal or other sheet material. The key feature herein is the novel utilization of conventional sheets of plywood or other structural sheet material to produce large areas of panels for inclusion in such systems.